A Retrospective Study on Anatomical Variants of the Uncinate Process: What the Radiologist Needs to Inform the Surgeons?

Abstract

Introduction: Uncinate Process (UP) is a crucial component of the anterior Osteomeatal Complex (OMC), which is a key area for the drainage and ventilation of the anterior group of paranasal sinuses. Aim: To determine the prevalence of various anatomic variants of the UP, like its varying superior attachment to vital structures like the lamina papayracea, skull base or the middle turbinate, angulation (medial or lateral), pneumatisation (uncinate bulla) and atelectatic UP using Computed Tomography (CT) images of the paranasal sinuses. Materials and methods: A retrospective cross-sectional study was conducted in the Radiodiagnosis department of a Tertiary care hospital from December 2019 through January 2020, to determine the prevalence of various anatomic variants of the UP. CT scans of the paranasal sinuses of 200 patients (males 112; females 98) in the age group of 17-70 years, were analysed in coronal view of bone window and the superior attachments of UP were classified based on the Stammberger and Hawke classification. Results: Of the total 200 images (400 sides), type I attachment to the Lamina Papyracea (LP) was most frequent 64.5% in 258 number of cases. Least common variation was the Type II attachment to the skull base 5% in 20 cases. UP pneumatisation (uncinate bulla) was less commonly seen variation in 25 cases. Normal vertical orientation of the UP was seen in 34 cases, Only two cases each of horizontal lateral and medial angulation and in both cases findings were unilateral. Conclusion: In order to determine the prevalence of various anatomic variation of the UP, especially its various superior attachments, the study examines the CT images of 200 patients and found that the variations in superior attachment found to be more frequent than the other variations and the commonest was the Type I, attachment to the LP directly or indirectly by attaching to the Agger Nasi Cells (ANC).

Keywords

• anatomical variations
• computed tomography
• paranasal sinuses
• osteomeatal complex